Effectiveness of Bacteria and Yeasts from Apple Orchards as Biological Control Agents of Apple Scab

Burr, Thomas J.; Matteson, M. Catherine; Smith, C.; Corral-Garcia, M. R.; Huang, Tze-Chung

doi:10.1006/bcon.1996.0019

Cited by 50 publications

(27 citation statements)

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“…P. syringae pv. lachrymans strain 508 was obtained from T. J. Burr (New York Agricultural Experiment Station) (8) and propagated on potato dextrose agar medium (Difco) at 28°C. P. syringae pv.…”

Section: Methodsmentioning

confidence: 99%

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Novel Cyclic Lipodepsipeptide from Pseudomonas syringae pv. lachrymans Strain 508 and Syringopeptin Antimicrobial Activities

Grgurina

Bensaci

Pocsfalvi

et al. 2005

Antimicrob Agents Chemother

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The syringopeptins are a group of antimicrobial cyclic lipodepsipeptides produced by several plant-associated pseudomonads. A novel syringopeptin, SP508, was shown to be produced as two homologs (A and B) by Pseudomonas syringae pv. lachrymans strain 508 from apple and to structurally resemble syringopeptin SP22. SP508 differed from SP22 and other syringopeptins by having three instead of four ␣,␤-unsaturated amino acids and a longer ␤-hydroxy acyl chain. Both SP508 and SP22 displayed growth-inhibitory activities against Mycobacterium smegmatis, other gram-positive bacteria, and yeasts but not against gram-negative bacteria. Structure-activity analyses of the SP508 and SP22 homologs indicated chemical structural features that lead to enhanced antimycobacterial activity by these pseudomonad cyclic lipodepsipeptides.Syringopeptins (SPs) are bacterial secondary metabolites belonging to a class of cyclic lipodepsipeptides produced by certain pathovars of the plant bacterium Pseudomonas syringae (1,2,25,36). Their peptide portions contain either 22 (SP22) or 25 (SP25) amino acids that are predominantly hydrophobic, valine and alanine in particular. About 70% of the chiral residues are of the D configuration, and there are four ␣,␤-unsaturated and two 2,4-diaminobutyric acid residues (2,17,21,30). An N-terminal residue dehydroaminobutyric acid (Dhb) is N acylated by a 3-hydroxylated fatty acid chain containing either 10 or 12 carbon atoms; these two types of chains are designated A and B homologs and are typically the more abundant and less abundant forms, respectively. The C-terminal carboxyl group is esterified by the hydroxyl group of the allo-Thr residue positioned at the distance of 7 residues, thus forming an eightmembered lactone macrocycle. So far, two SP25 and three SP22 forms have been identified. SP25 is produced by P. syringae pv. syringae strains that have been isolated from infected millet (B359), citrus (B427) (2), and wheat (M1) (1) as well as from the wheat pathogen P. syringae pv. atrofaciens (36). An isoform differing in the C-terminal residue, SP25-Phe, was detected in a laurel-infecting strain (30). SP22 is produced by a P. syringae pv. syringae strain isolated from pear (B301) (2), and variants are produced by P. syringae pv. syringae strains from sugar cane (SP[SC]) (21) and bean (SPPhv) (17). Each SP-producing P. syringae strain produces one type of SP together with a smaller, nine-amino-acid-containing cyclic lipodepsipeptide-either syringomycin (13, 32), syringotoxin (3), syringostatin (13), or pseudomycin (5).The SPs are produced in infected plant tissues (12, 15), and they play roles as virulence factors in plant diseases (31). The phytotoxic physiological effects of the SPs were demonstrated with isolated plant mitochondria (10) and tobacco protoplasts (18). Lipid bilayer studies have revealed that the probable mechanism of action involves insertion into target membranes with formation of ion channels and consequent ion imbalances that lead to cell death (9, 18). In addition to their phyto...

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Section: Methodsmentioning

confidence: 99%

“…lachrymans strain 508. This organism was isolated in a New York apple orchard and shown to be antagonistic to Venturia inequalis, the causative agent of apple scab (8). We show that SP508 is a novel SP and a structural variant of SP22.…”

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confidence: 89%

Novel Cyclic Lipodepsipeptide from Pseudomonas syringae pv. lachrymans Strain 508 and Syringopeptin Antimicrobial Activities

Grgurina

Bensaci

Pocsfalvi

et al. 2005

Antimicrob Agents Chemother

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“…While in vitro antibiosis has been widely used to select potential biological control agents of foliar diseases, studies demonstrating antibiosis to be an important attribute in biological control are scarce. In a test using 931 bacterial and yeast isolates for control of apple scab caused by Venturia inaequalis, no correlation was observed between in vitro antibiosis and ability of these microorganisms to suppress the disease on apple seedlings (4). In another study, in vitro antibiotic production in a collection of epiphytic bacteria was not correlated with the ability to control ice nucleation active (Ice ϩ ) Pseudomonas syringae strains on corn leaves (15).…”

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confidence: 96%

Assessment of the Importance of Similarity in Carbon Source Utilization Profiles between the Biological Control Agent and the Pathogen in Biological Control of Bacterial Speck of Tomato

Wilson

2002

Appl Environ Microbiol

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Bacterial speck of tomato, caused by Pseudomonas syringae pv. tomato, was used to determine whether similarity in carbon source utilization between a preemptive biological control agent and the pathogen was significant in determining the ability of the bacterium to suppress disease. Similarity in carbon source utilization was quantified as the ratio of the number of tomato carbon sources utilized in vitro by the biological control agent to the number of tomato carbon sources utilized in vitro by the target pathogen (the niche overlap index [NOI]). Suppression of the disease was quantified as the percent reduction in disease severity compared to the pathogen-only control when nonpathogenic bacteria were applied to foliage 48 h prior to the pathogen. In the collection of 36 nonpathogenic bacterial strains, there was a significant (P < 0.01), but weak (r 2 ‫؍‬ 0.25), correlation between reduction in disease severity and similarity in carbon source utilization, suggesting that similarity in carbon source use was significant in determining ability to suppress disease. The relationship was investigated further using catabolic mutants of P. syringae strain TLP2, an effective biological control agent of speck. Catabolic mutants exhibited lower levels of similarity (NOI ‫؍‬ 0.07 to 0.90) than did wild-type TLP2 (NOI ‫؍‬ 0.93). With these catabolic mutants there was a significant (P < 0.01), and stronger (r 2 ‫؍‬ 0.42), correlation between reduction in disease severity and similarity in carbon source utilization. This suggests that similarity in carbon source utilization was a more important component of biological control ability for the catabolic mutants than for the nonpathogenic bacteria. Together, these studies indicate that suppression of bacterial speck of tomato was correlated with nutritional similarity between the pathogenic and nonpathogenic bacteria and suggest that preemptive utilization of carbon sources was probably involved in the biological control of the disease by both the naturally occurring nonpathogenic bacteria and the catabolic mutants.

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“…This strain became famous as the first gene-engineered microorganism released into the environment after the genes coding for its ice nucleation activity were removed (40). Other examples are P. syringae strain TLP2, isolated from a healthy potato leaf (41), and P. syringae strain 508, isolated from an apple leaf on an orchard floor (7). P. syringae TLP2 and P. syringae 508 are both examples of biocontrol strains.…”

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confidence: 99%

“…P. syringae TLP2 was found to moderately control pathogenic P. syringae pv. tomato strains when it was applied to tomato (Solanum lycopersicum) (64), and P. syringae 508 was found to have exceptional antimicrobial activity against the apple scab fungus Venturia inaequalis (7). The antifungal activity of P. syringae 508 is believed to be due in part to the production of the toxin syringopeptin.…”

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confidence: 99%

Naturally Occurring Nonpathogenic Isolates of the Plant Pathogen Pseudomonas syringae Lack a Type III Secretion System and Effector Gene Orthologues

et al. 2008

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Pseudomonas syringae causes plant diseases, and the main virulence mechanism is a type III secretion system (T3SS) that translocates dozens of effector proteins into plant cells. Here we report the existence of a subgroup of P. syringae isolates that do not cause disease on any plant species tested. This group is monophyletic and most likely evolved from a pathogenic P. syringae ancestor through loss of the T3SS. In the nonpathogenic isolate P. syringae 508 the genomic region that in pathogenic P. syringae strains contains the hrp-hrc cluster coding for the T3SS and flanking effector genes is absent. P. syringae 508 was also surveyed for the presence of effector orthologues from the closely related pathogenic strain P. syringae pv. syringae B728a, but none were detected. The absence of the hrp-hrc cluster and effector orthologues was confirmed for other nonpathogenic isolates. Using the AvrRpt2 effector as reporter revealed the inability of P. syringae 508 to translocate effectors into plant cells. Adding a plasmid-encoded T3SS and the P. syringae pv. syringae 61 effector gene hopA1 increased in planta growth almost 10-fold. This suggests that P. syringae 508 supplemented with a T3SS could be used to determine functions of individual effectors in the context of a plant infection, avoiding the confounding effect of other effectors with similar functions present in effector mutants of pathogenic isolates.Pseudomonas syringae is probably the most intensively studied bacterial plant pathogen for which molecular interactions with host and nonhost plants have been dissected in great detail (16,43,50). P. syringae is a member of the Gammaproteobacteria and comprises strains isolated from dozens of cultivated, ornamental, and wild plants. According to the current taxonomy, isolates are grouped into different pathovars based on the plant host from which they were isolated (65). The diseases that P. syringae strains cause range from foliar spot diseases to blights, stripes, and cankers (1). Bacteria are transmitted mainly by rain and wind, can survive for periods of time on leaf surfaces as epiphytes without causing disease, and then enter leaves either through natural openings like stomata or through wounds and finally reach high population densities in the intercellular plant spaces and cause visible disease symptoms (26). Recently, P. syringae isolates have been found in clouds, rain, snow, and river epilithion, suggesting that these environments are important inoculum sources (44).P. syringae is able to cause diseases in its hosts because of its ability to suppress plant defenses elicited by microbe-associated molecular patterns (MAMPs) or pathogen-associated molecular patterns (PAMPs) like flagellin (23). These defenses are called PAMP-triggered immunity (PTI) (11). Suppression of PTI is accomplished by effector proteins that are translocated from P. syringae into plant cells by means of a type III secretion system (T3SS) and by toxins (for example, coronatine) (38, 43). However, on some plants, effectors are directl...

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Effectiveness of Bacteria and Yeasts from Apple Orchards as Biological Control Agents of Apple Scab

Cited by 50 publications

References 0 publications

Novel Cyclic Lipodepsipeptide from Pseudomonas syringae pv. lachrymans Strain 508 and Syringopeptin Antimicrobial Activities

Novel Cyclic Lipodepsipeptide from Pseudomonas syringae pv. lachrymans Strain 508 and Syringopeptin Antimicrobial Activities

Assessment of the Importance of Similarity in Carbon Source Utilization Profiles between the Biological Control Agent and the Pathogen in Biological Control of Bacterial Speck of Tomato

Naturally Occurring Nonpathogenic Isolates of the Plant Pathogen Pseudomonas syringae Lack a Type III Secretion System and Effector Gene Orthologues

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